The present invention relates to a system and method for loading software into field test equipment. More particularly, the invention relates to loading the correct version of application software into field test equipment that may be connected to one of a number of base transceiver stations in a cellular telecommunications system.
The principles of operation of a mobile communications system, such as a cellular telephone system, are well known. Essentially, the system is divided into a land-based system and a radio system. Mobile subscribers communicate with any one of a number of base transceiver stations (BTSs) by means of the radio interface. The BTSs are geographically distributed so that as a mobile subscriber roams, he or she will be within the service area of at least one of the BTSs in the system. If, when a call is in progress, the mobile subscriber moves out of range of its assigned BTS and into the range of a neighboring BTS, the cellular telephone system will reassign the mobile subscriber to the neighboring BTS, in a process called "handoff." Management of call handoff, as well as all other aspects of call initiation and termination, are handled by various components of the land based system. The land-based system is also responsible for the routing of calls between mobile subscribers, and for interfacing calls to the public switched telephone network (PSTN).
The many functions of the land-based system are not performed by a single hardware unit, but are instead distributed among a number of components, which are coupled together in a communications network. These components include the above-described BTSs, which provide the radio link between the land-based system and the mobile subscribers. The land-based system may also include a base station controller (BSC) for controlling the high-level operation of as many as one hundred or more BTSs. Switching, call handoff, and other functions are performed by a mobile switching center (MSC) that is coupled to the BSCs in the system.
Because proper operation of the BTSs is of vital importance to the system, routine maintenance is regularly scheduled and performed. Such maintenance is typically performed with the assistance of an operations and maintenance terminal (OMT), which is a type of field test equipment. FIG. 1 illustrates the prior art components and method for performing this maintenance work. As shown in the drawing, a BSC 101 is connected to a number n of BTSs 103-1 . . . 103-n, where in a typical system n may be greater than one hundred. If it is desired to perform test and maintenance operations on the BTS 103-1, an OMT 105 is connected to the BTS 103-1 by means of an interface 107, which may be an RS-232 interface. In FIG. 1, this connection is illustrated by a dotted line, to indicate that the connection is not a permanent one. That is, after the testing and maintenance have been performed, the OMT 105 may be disconnected from the BTS 103-1, and brought to a different BTS 103-i (i=2, . . . , n), where it may again be used for performing test and maintenance operations.
The OMT 105 includes components that are typically found in a portable computer, such as a processor 109, memory 111 and floppy disk drive 113. To perform the test and maintenance operations, an operator must insert a diskette 115 into the floppy disk drive 113, and load the OMT application software, which is contained on the diskette 115, into the memory 111. After it has been loaded into the memory 111, the operator may invoke the OMT application software to begin the tests.
Upon invocation, the first thing that the loaded OMT application software does is attempt to establish communication with a counterpart BTS program 117 that is installed and running in the BTS 103-1. After communication has been established between the OMT 105 and the BTS 103-1, the test and maintenance procedures are performed under the direction of the loaded OMT application software.
Like most application software, the BTS program 117 is periodically revised and improved, sometimes to account for changes in the hardware features that comprise the BTS 103-1. As a result, the BTS program 117 is associated with a version number that particularly identifies which revision of software is in the BTS 103-1. For the OMT 105 to be able to perform its tasks, it is necessary that the OMT application software 115 be a version that corresponds to the version number of the BTS program 117. If this is not the case, the two programs (i.e., BTS program 117 and OMT application software 115) will be unable to cooperate with one another. What's worse is that the operator may be given no indication of this other than the fact that the OMT 105 is unable to establish communications with the BTS 103-1, which could erroneously be construed as an indication that a more serious hardware problem exists.
In the prior art, this problem has been addressed by requiring that the OMT operator have available a number of different versions of the OMT application software on various floppy disks 115. With this solution, the OMT operator has to keep track of which version of OMT application software belongs with which of the BTSs 103-1 . . . 103-n. Whenever a new version of BTS software 117 is made available, the prior art requires that a corresponding new floppy disk, containing OMT application software, be distributed to the OMT operator. This is particularly cumbersome because the BTS software 117 itself is not distributed on floppy disks, but is instead downloaded directly from the BSC 101 in accordance with well-known methods, such as those generally described in copending U.S. application Ser. No. 08/237,988 to Dahlin et al., filed May 4, 1994 entitled "Providing a Master Device With Slave Device Capability Information" which is commonly assigned to the same assignee as the present application, and which is hereby incorporated by reference. Thus, the distribution and cataloging of diskettes is performed only for the benefit of being able to supply the correct version of OMT application software 115 to the OMT 105. Consequently, it is desirable to find a better way of distributing the correct software to the OMT 105 for use with any one of the BTSs 103-1 . . . 103-n.